Re: Newbie Developer Question - Mailing list pgsql-novice

From Matthew Campbell
Subject Re: Newbie Developer Question
Date
Msg-id c2cc277f0702010858q16e6ae21qfece5981e59c06af@mail.gmail.com
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In response to Re: Newbie Developer Question  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Newbie Developer Question
List pgsql-novice
Thanks so much for the help.  _hash_first, and _hash_next all take the scan object as a parameter.  How do you create or get a scan object?  hashbeginscan looks like it sets up a scan and returns it, but it takes the number of keys and the array of scan keys.  Where do we get these arguments from?


-Matt

On 2/1/07, Tom Lane <tgl@sss.pgh.pa.us > wrote:
"Matthew Campbell" < mtthw.cmpbll@gmail.com> writes:
> ... We've been digging through the src/backend/access/hash/
> and we're having a hard time figuring out the correct way to walk through
> items in a page.  Is this what the hashbeginscan() method is for?

No, hashbeginscan doesn't do much at all except initialize state.  The
interesting stuff happens during successive hashgettuple calls ---
specifically _hash_first the first time and _hash_next on later calls.

                        regards, tom lane

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